Deposition of polysilicon using a remote plasma and in situ generation of UV light.

ABSTRACT

A processing apparatus and method for depositing doped or undoped polysilicon on a wafer utilizing a single process chamber to heat the wafer, provide a silicon comtaining gas, and if desired, an appropriate dopant gas to the chamber with the excitation energy being provided by either or both of a remotely generated plasma form and illumination of the wafer with an in situ generated ultraviolet energy.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation in part of application Ser.No. 074,373, filed 7/16/87, now abandoned, entitled Processing Apparatusand Method.

The present application incorporates by reference each of the followingapplications which are related cases of common assignee and containrelated subject matter:

Ser. No. 060,991, filed 06/12/87, pending, Vacuum Slice Carrier; whichis a continuing application of Ser. No. 790,918, filed 10/24/85 byDavis, Cecil and Matthews, Robert; now abandoned;

Ser. No. 060,976 filed 06/12/87, pending, Advanced Vacuum Processor;which is a continuing application of Ser. No. 790,708, filed 10/24/85 byDavis, Cecil; Spencer, John; Wooldridge, Tim; and Carter, Duane; nowabandoned;

U.S. Pat. No. 4,687,542, issued Aug. 18, 1987, entitled VacuumProcessing System by Davis, Cecil; Matthews, Robert; and Hildenbrand,Randall;

Ser. No. 790,707, filed 10/24/85, pending, entitled Apparatus forPlasma-Assisted Etching by Davis, Cecil; Carter, Duane; and Jucha,Rhett;

Ser. No. 061,017, filed 06/12/87, pending, entitled Integrated CircuitProcessing System; which is a continuing application of Ser. No.824,342, filed 1/30/86 by Davis, Cecil; Bowling, Robert; and Matthews,Robert; and

Ser. No. 915,608, filed 10/06/86, pending, entitled Movable ParticleShield by Bowling, Robert; Larrabee, Graydon; and Liu, Benjamin.

Ser. No. 074,448, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Matthews, Robert; Loewenstein, Lee;Abernathy, Joe; and Wooldridge, Timothy;

Ser. No. 075,016, filed 7/17/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Loewenstein, Lee; Matthews, Robert; andJones, John;

Ser. No. 073,943, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; Rose, Alan; Kennedy, Robert III;Huffman, Craig; and Davis, Cecil;

Ser. No. 073,948, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee;

Ser. No. 073,942, filed 7/16/87, pending entitled Processing Apparatusand Method; by Jucha, Rhett; and Davis, Cecil;

Ser. No. 074,419, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; and Matthews, Robert;

Ser. No. 074,377, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Jucha, Rhett; Hildenbrand, Randall;Schultz, Richard; Loewenstein, Lee; Matthews, Robert; Huffman, Craig;and Jones, John;

Ser. No. 074,398, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Loewenstein, Lee; Jucha, Rhett; Matthews,Robert; Hildenbrand, Randall; Freeman, Dean; and Jones, John;

Ser. No. 074,456, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Jucha, Rhett; Luttmer, Joseph; York, Rudy;Loewenstein, Lee; Matthews, Robert; and Hildenbrand, Randall;

Ser. No. 074,399, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Jucha, Rhett; and Davis, Cecil;

Ser. No. 074,450, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Jucha, Rhett; Davis, Cecil; and Jones, John;

Ser. No. 074,375, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Jucha, Rhett; Carter, D.; Davis, Cecil; and Crank S.;

Ser. No. 074,411, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Jucha, Rhett; Davis, Cecil; Carter, D.; Crank, S.; andJones, John;

Ser. No. 074,390, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Jucha, Rhett; Davis, Cecil; and Crank S.;

Ser. No. 074,114, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Loewenstein, Lee; Freeman, Dean; andBurris, James;

Ser. No. 074,373, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Freeman, Dean; Burris, James; Davis, Cecil; andLoewenstein, Lee;

Ser. No. 074,391, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Freeman, Dean; Burris, James; Davis, Cecil; andLoewenstein, Lee:

Ser. No. 074,415, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Freeman, Dean; Burris, James; Davis, Cecil; Loewenstein,Lee;

Ser. No. 074,451, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Luttmer, Joseph; Davis, Cecil; Smith, Patricia; York,Rudy; Loewenstein, Lee; and Jucha, Rhett;

Ser. No. 073,945, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Luttmer, Joseph, Davis, Cecil; Smith, Patricia; and York,Rudy;

Ser. No. 073,936, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Luttmer, Joseph, Davis, Cecil; Smith, Patricia; and York,Rudy;

Ser. No. 074,111, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Luttmer, Joseph, York, Rudy; Smith, Patricia; and Davis,Cecil;

Ser. No. 074,386, filed 7/16/87, pending, entitled Processing Apparatusand Method; by York, Rudy; Luttmer, Joseph; Smith, Patricia; and Davis,Cecil;

Ser. No. 074,407, filed 7/16/87, pending, entitled Processing Apparatusand Method; by York, Rudy; Luttmer, Joseph; Smith, Patricia; and Davis,Cecil;

Ser. No. 075,018, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Abernathy, Joe; Matthews, Robert;Hildenbrand, Randall; Simpson, Bruce; Bohlman, James; Loewenstein, Lee;and Jones, John;

Ser. No. 074,112, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Matthews, Robert; York, Rudy; Luttmer,Joseph; Jakubik, Dwain; and Hunter, James;

Ser. No. 074,449, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Smith, Greg; Matthews, Robert; Jones, John;Smith, James; and Schultz, Richard;

Ser. No. 074,406, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Freeman, Dean; Matthews, Robert; Tomlin,Joel;

Ser. No. 073,941, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Loewenstein, Lee; Tipton, Charlotte; Smith,Randee, Pohlmeier, R.; Jones, John; Bowling, Robert; and Russell, I;

Ser. No. 074,371, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; and Davis, Cecil;

Ser. No. 074,418, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Fisher, Wayne;

Ser. No. 073,934, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Fisher, Wayne; Bennett, Tommy; Davis, Cecil; andMatthews, Robert;

Ser. No. 074,403, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Matthews, Robert; and Fisher, Wayne;

Ser. No. 075,019, filed 7/17/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Freeman, Dean; Matthews, Robert; andTomlin, Joel;

Ser. No. 073,939, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Abernathy, Joe; Matthews, Robert,Hildenbrand, Randy; Simpson, Bruce; Bohlman, James; Loewenstein, Lee;and Jones, John;

Ser. No. 073,944, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Cecil, Davis and Jucha, Rhett;

Ser. No. 073,935, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Liu, Jiann; Davis, Cecil; and Loewenstein, Lee;

Ser. No. 074,129, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; Freeman, Dean; and Davis, Cecil;

Ser. No. 074,455, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; Freeman, Dean; and Davis, Cecil;

Ser. No. 074,453, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; Freeman, Dean; and Davis, Cecil;

Ser. No. 073,949, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; and Davis, Cecil;

Ser. No. 074,379, filed 7/16/87 pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; and Davis, Cecil;

Ser. No. 073,937, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; and Davis, Cecil;

Ser. No. 074,425, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee; Davis, Cecil; and Jucha, Rhett;

Ser. No. 073,947, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Loewenstein, Lee; and Jucha, Rhett;

Ser. No. 074,452, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Jucha, Rhett; Davis, Cecil; and Loewenstein, Lee;

Ser. No. 074,454, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Jucha, Rhett; Davis, Cecil; and Loewenstein, Lee;

Ser. No. 074,422, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Matthews, Robert; Jucha, Rhett; andLoewenstein, Lee;

Ser. No. 074,113, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; Matthews, Robert; Loewenstein, Lee; Jucha,Rhett; Hildenbrand, Randy; and Jones, John;

Ser. No. 073,940, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; and Matthews, Robert;

Ser. No. 075,017, filed 7/17/87, pending, entitled Processing Apparatusand Method; by Loewenstein, Lee;

Ser. No. 073,946, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; and Matthews, Robert; and

Ser. No. 073,938, filed 7/16/87, pending, entitled Processing Apparatusand Method; by Davis, Cecil; and Matthews, Robert;

The following application is a related case of common assignee and isbelieved to have the same filing date and contain related subjectmatter:

Ser. No. 117,708, filed 11/5/87, pending entitled Processing Apparatusand Method; by Freeman, Dean; and Burris, James.

BACKGROUND OF THE INVENTION

1. Field Of The Invention

The present invention relates to a method for manufacturing integratedcircuits and other electronic devices. More particularly, it relates toan improved process for the deposition of polysilicon on a semiconductorwafer.

2. Description Of The Related Art

The use of plasma reactors for various etching procedures is well knownin the art. It is also well known in the art that the use of plasmareactors can enhance the deposition of various conductive or insulatinglayers on a semiconductor wafer. In addition, it is known that the useof ultraviolet light also increases the deposition rate for bothconductive and insulating layers and that the deposition rate isdirectly proportional to the number of photons striking the surface. Itis also known that placing a seemingly transpareint window in the pathof ultraviolet photons reduces the number of photons reaching thesurface of the object at which the beam is directed.

The cross-related cases describe devices and methods for the vacuumprocessing of semiconductor wafers. They disclose methods formanipulating wafers, and etching and depositing conductive andinsulating materials in vacuum processors. In addition, thecross-related cases have described devices and methods which cansimultaneously couple the use of several energy sources (e.g., radiofrequency, microwave, light and ultraviolet light) during a singleprocessing step. One such device is disclosed in a related U.S. Pat.Application of a common assignee (Ser. No. 074,398 filed 7/16/87).

These devices and methods have helped to reduce to a very low value theparticulate contamination of wafers undergoing manufacturing processes.They have reduced potential particulate ingress, particulate settlingtime and the potential for process generated contaminants.

They also allow a multiplicity of steps to be performed in the samevacuum processor without moving the wafer (e.g., Ser. No. 074,114 filed7/16/87). They also allow post deposition clean up of the chamber. Thesedevices and methods, have, therefore, added to the efficiency,uniformity, and yield of the semiconductor manufacturing process.

The pace of development in the semiconductor industry creates, however,a situation in which manufacturers must constantly strive to increasethroughput and yield in order to remain competitive. Thus, each newadvance must be used optimally.

The advances in the processing technology described in the cross-relatedcases, have, therefore, created a need for optimized process. In arelated case by a common assignee (Ser. No. 074,373 filed 7/16/87),there is disclosed a method for the deposition of undoped polysiliconusing silane as a feed gas. The efficiency of processing could beimproved if deposition and doping could be accomplished in a singlestep. There is, therefore, a need for deposition method which candeposit both doped and undoped polysilicon and utilize different siliconsources as feed gasses.

SUMMARY OF THE INVENTION

The present invention improves the method for depositing polysilicon ona wafer by allowing the deposition of polysilicon using silicon sourcesother than silane and by allowing the deposition of doped or undopedpolysilicon.

In a useful embodiment, a wafer is transferred into a vacuum processingmodule and the chamber purged with an appropriate gas. A pressure lessthan ambient is applied to the processing chamber and the chamber isthen radiantly heated through a quartz window. A remote plasma isgenerated using a silicon containing gas (e.g., silane or disilane), andif desired, an appropriate dopant (e.g. a phosphorous or boroncontaining gas) as feed gasses. The plasma is directed to the face ofthe wafer and the face of the wafer is illuminated with ultravioletenergy generated inside the processing module and directly coupled tosaid face.

The advantages are set forth within and toward the end of theDescription of the Preferred Embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described with reference to theaccompanying drawings, wherein:

FIG. 1 shows a sample embodiment of a load lock which is compatible withvacuum processing and transport of semiconductor integrated circuitwafers.

FIG. 2 shows a sample wafer transfer structure, in a process station,wherein the wafer is placed onto three pins by the transfer arm 28reaching through the inter-chamber transfer port 30 from the adjacentvacuum load lock chamber 12.

FIG. 3 shows a closer view of a sample embodiment of a multi-wafervacuum wafer carrier 10, docked onto the position registration platform18 inside a load lock like that of FIG. 1.

FIG. 4 shows an embodiment which includes the capability for processenhancement by ultraviolet light generated in situ and also thecapability is also provided for providing activated species (generatedby gas flows through an additional plasma discharge which is remote fromthe wafer face) to the wafer face. The module is shown in a processstation which includes only one module and one load lock, but can alsobe used in embodiments with multiple chambers.

FIG. 5 shows a physical configuration for a process station which can beused for implementing some of the embodiments described herein.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides new concepts in semiconductor processingmethods and apparatus. A useful embodiment will now be discussed ingreater detail, but it must be appreciated that the concepts which areincluded in this embodiment could also be used in many otherembodiments, and the scope of the invention is not delimited by theparticular examples shown.

FIG. 1 shows a sample embodiment of a vacuum wafer carrier 10 inside avacuum load lock chamber 12. The vacuum wafer carrier 10 is also shown,in slightly greater detail, in FIG. 2.

The vacuum wafer carrier 10 is shown with its door 14 open. The door 14is mounted in a pivotal manner to one side (the left side as shown inFIGS. 1 and 2) of the main body of carrier 10 by, for example, hinges(not shown). The door 14 has a vacuum seal 13 (FIG. 2) where it mateswith the body of the vacuum wafer carrier, so that the interior ofvacuum wafer carrier 10 can be maintained for several days and possiblyfor several tens of days, without enough leakage to raise the internalpressure above 10⁻³ Torr, for example, while the exterior of carrier 10is subjected to the atmosphere.

The vacuum wafer carrier 10 is adapted to dock with a positionregistration platform 18. The position registration platform 18 is onlypartially visible in FIG. 1, but is shown in more detail in FIG. 2. Whena vacuum wafer carrier 10 is placed inside the vacuum load lock chamber12, the position of the vacuum wafer carrier 10 will, therefore, beaccurately known. The vacuum wafer carrier 10 has ears 16 which engagevertical slots 17 fixed to the position registration platform 18. Thevacuum wafer carrier 10 can be slid into these slots until it rests onthe position registration platform 18, and thereby assure that theposition of the vacuum wafer carrier 10 is definitely known. It is alsouseful for the position registration platform 18 to include two taperedpins 21. As shown in FIG. 2, the pins 21 are both conical shaped butthey can be of different shapes, for example, one conical and onewedge-shaped. The pins 21 are positioned to engage tapered holes 23 inthe underside of the vacuum wafer carrier 10 when it is lowered withears 16 engaged with slots 17. A wide variety of other arrangementscould be used to assure mechanical registration. Thus, the use of slots17, ears 16, and pins 21 bring carrier 10 and chamber 12 into alignment(or mechanical registration).

The vacuum wafer carrier 10 also has a safety catch 15 on it whichsecures the door 14 from opening due to external forces beingaccidentally applied. An ear 500 extends from the side of the door 14away from the hinges (not shown) which attach it to the main body ofcarrier 10. The safety catch 15 can also be used to hold the door 14closed if the carrier 10 is used as a non-vacuum carrier. The ear isadapted to engage with a safety catch 15 rotatably mounted on the side(the right side as shown in FIG. 2) of carrier 10. Under normalconditions of transport, however, this safety catch is not needed, sinceatmospheric pressure holds the door 14 shut against the internal vacuumof the vacuum wafer carrier 10. When the vacuum wafer carrier 10 isplaced inside the vacuum load lock chamber 12 by engaging ears 16 withslots 17, a fixed finger 19 will engage the safety catch 15 and rotateit (upward as shown in FIG. 2) away from ear 500 to release it, so thatthe door 14 can be opened. Fixed finger 19 extends upward from platform18 as shown in FIG. 2.

When the vacuum wafer carrier 10 is docked with the positionregistration platform 18, the door 14 will also be engaged with the topof door opening shaft 24. The door 14 can be provided with a shallowgroove (not shown) in its underside, which mates with a finger and arm25 on the top of the door opening shaft 24. The arm 25 is located toengage the door 14 near its attachment to the main body of carrier 10 inorder to rotate the door 14 as desired. Thus, after the load lock hasbeen pumped down so that differential pressure no longer holds the door14 closed, the door can be opened by rotating (clockwise as shown inFIG. 2) door opening shaft 24. The door can be closed by rotating shaft24 counterclockwise as shown in FIG. 2.

After the vacuum wafer carrier 10 is placed in the vacuum load lockchamber 12 (FIG. 1) and closed the load lock lid 20, a purge (with drynitrogen or other clean gas), which can be at high pressure, is usefullyapplied through the manifold 22 (FIG. 1) inside the load lock lid 20.The manifold 22 includes holes in lid 20, a connection with a source ofthe gas into the holes in lid 20, and openings from the holes in thebottom of lid 20. The gas flows from the source through the holes in lid20 and exits downward from lid 20 through the openings. The gas from themanifold 22 provides vertical flow which tends to transport particlesdownward. The gas flow from the manifold 22 also helps to remove some ofthe large particles which may have collected on the vacuum wafer carrier10 during its exposure to atmospheric conditions.

After this initial purge stage (e.g. for 30 seconds or more), thechamber is then slowly pumped down to 10⁻³ Torr or less. This stage ofthe pump down should be relatively slow, in order not to stir up randomparticulates. That is, while low pressure do permit particles to fallfrom the air, those particles will still be available on the bottom ofthe chamber, and must not be stirred up if this can be avoided.

In order to make sure that the airborne particulates have actuallyfallen out of the chamber air, the interior of the vacuum load lock canthen be allowed to stay at 10⁻³ or 10⁻⁴ Torr for a few seconds, to makesure that all of the particles which are able to fall out of the airwill do so.

The use of the carrier 10 and chamber 12 in the manner described abovegreatly reduce the problems of airborne particulates, which have alwaysbeen the dominant type of particulate transport, so that the problem ofballistically transported particulates can now be usefully addressed.

A sloped bottom and polished sidewalls for the load lock may be used asa modification of chamber 12. This would reduce the population ofparticulates sticking to the sidewalls and bottom which can be sentdisturbed by mechanical vibration.

Note that vacuum gauges 62 (FIG. 1) are connected to the interior of thevacuum load lock chamber 12. The vacuum gauges 62 include ahigh-pressure gauge (such as a thermocouple), a low pressure gauge (suchas an ionization gauge), and a differential sensor which accuratelysenses when the load lock interior pressure has been equalized with theatmosphere. The door of a vacuum wafer carrier 10 is not opened untilthese gauges indicate that desired vacuum has been achieved inside theload lock.

After the chamber is brought to soft vacuum, the gate or isolation valve39 can be opened to connect the pump 38 to the interior of the loadlock, and the pump 38 can then be operated to bring the pressure down to10 to the -3 Torr or less.

At this point, the pressure inside the vacuum wafer carrier 10 and thevacuum load lock chamber 12 are more or less equalized, and the door 14can be opened by activating by an door drive motor 26 (FIG. 2), which isconnected to door opening shaft 24 through a vacuum feedthrough 33.Motor 26 rotates shaft 24 in a clockwise direction as shown in FIGS. 1and 2 to open the door 14 and in a counterclockwise direction to closethe door 14. Two sensor switches (not shown) are included inside thevacuum load lock chamber 12, to ascertain when the door 14 is in itsfully opened position, and when the door 14 is fully shut. Thus, afterthe load lock chamber 12 has been pumped down and allowed to sit for afew seconds, the door opening shaft 24 is rotated in a clockwisedirection to open the door 14, until one sensor switch detects that thedoor is fully open.

During this time, the transfer arm 28 is kept in its home position at anelevation below the bottom of the door, so that the door 14 hasclearance to open. After the sensor switch detects that the door 14 isfully open, the transfer arm 28 can begin to operate. In order to closethe door 14, shaft 24 is rotated in a counterclockwise direction untilthe other sensor switch detects that the door 14 is closed.

The transfer arm 28 has two degrees of freedom. The arm is capable ofboth vertical and horizontal movement. One direction of motion permitsthe transfer arm 28 to reach into vacuum wafer carrier 10 or throughinter-chamber transfer port 30 into the adjacent process module, forexample, process module 570 (FIG. 4). The other degree of freedomcorresponds to vertical motion of the transfer arm 28, which permitsselection of a wafer inside the vacuum wafer carrier 10 to remove, orwhich slot a wafer is placed into during a transfer operation.

An elevator drive motor 32 provides the elevation of the transfer arm28, and the arm drive motor 34 provides the extension and retraction ofthe transfer arm 28. Neither of these motors requires a vacuumfeedthrough since they are housed inside the exhaust manifold 36. Themanifold 36, as shown in FIG. 1, has a cylindrical shape and extendsfrom the bottom of chamber 12 downward. The manifold also extendsthrough and is attached to the bottom of chamber 12 a short distanceinto chamber 12. The pump 38 is at the end of manifold 36 away from itsattachment to chamber 12. The motor 26 also extends downward fromchamber 12. Pump 38 can be, for example, a turbomolecular pump. Theexhaust manifold 36 does not open directly into the vacuum load lockchamber 12, but instead has apertures 40 around its top (the end ofmanifold 36 extending into chamber 12). Thus, the exhaust manifold 36 isconfigured so that there is not a line of sight path from the elevatordrive motor 32, the arm drive motor 34, or from the pump 38 to thevacuum load lock chamber 12. This reduces ballistic transport ofparticulates from these moving elements into the load lock chamber. Thearrangement shown in FIG. 1 has been found useful but other arrangementsare possible to provide the necessary transportation of the wafer 48.

The elevator drive motor 32 is connected to drive a sub-platform 42 upand down, and the arm drive motor 34 is mounted on this sub-platform 42within the manifold 36. Motor 34 is fixed within manifold 36. The driveshaft of motor 32 drives a screw 510. Screw 510 passes through threadsin sub-platform 42 to drive sub-platform 42 up or down dependent on thedirection of rotation of the drive shaft of motor 32. Three rods 520,521, and 522 pass through and are capable of sliding engagement withsub-platform 42. The rods are affixed to the top of manifold 36. Alsoaffixed to subplatform 42 is a tubular support 46. This linkage withinthe manifold 36 allows the transfer 28 to easily move vertically.

Another linkage is provided inside the rotatable transfer arm support 44which permits the transfer arm 28 to move very compactly. The tubularsupport 46 extends form sub-platform 42 up through the top of manifold36. The rotatable transfer arm support 44 is connected to to be drivenby a rotating rod (not shown) within tubular support 46. The tubularsupport 46 is fixed to arm support 44. Thus, the rotating rod is drivenby the arm drive motor 34 and in turn drives arm support 44 and therotatable transfer arm support 44 is mounted on a tubular support 46which does not rotate but moves up and down. An internal chain andsprocket linkage is used so that the joint between rotatable transferarm support 44 and transfer arm 28 moves with twice the angular velocityof the joint between rotatable transfer arm support 44 and tubularsupport 46. Of course, many other mechanical linkages couldalternatively be used to accomplish this. This means that, when therotatable transfer arm support 44 is in its home position, a wafer 48will be supported approximately above the tubular support 46, but whenthe rotatable transfer arm support 44 is rotated 90 degrees with respectto the tubular support 46, the transfer arm 28 will have been rotated180 degrees with respect to the rotatable transfer arm support 44, sothe transfer arm can either extend straight into the vacuum wafercarrier 10 or else straight through the inter-chamber transfer port 30into the adjacent processing chamber. This linkage is described ingreater detail in U.S. Pat. No. 4,659,413 issued to Davis et al on Apr.21, 1987, which is hereby incorporated by reference.

The transfer arm 28 is a thin piece of spring steel, e.g. 0.030 inchthick. The transfer arm 28 has 3 pins 50 (FIGS. 1 and 3) on it tosupport the wafer 48. Each of the 3 pins 50 includes a small cone 52(FIG. 3) on a small shoulder 1900 (FIG. 3). The small cones 52 and smallshoulders 1900 can be made of a material which is soft enough to notscratch silicon. For example, these portions, which are the onlyportions of transfer arm 28 which actually touch the wafers beingtransported, can be made of a high-temperature plastic (i.e. a plasticwith a relatively low propensity to outgas under vacuum) such as Ardel(a thermoplastic phenyl acrylate, made by Union Carbide) or Delrin. Notethat the use of a small cone 52 at the center of each of the 3 pins 50permits very slight misalignments of the wafer to the transfer arm 28 tobe corrected. In other words the system of wafer transport describedhere is a stable mechanical system, wherein small misalignments duringsuccessive operations will not accumulate, but will be damped out. Thecontact with the wafer 48 and the pins 50 are only at the edge of thewafer.

Note that, in the positioning of the wafer 48 as shown, one of the 3pins 50 rests against the flat portion 56 (FIG. 2) on the circumference49 (FIG. 2) of wafer 48. This means that, in this embodiment, the 3 pins50 on the transfer arm 28 do not define a circle of the same diameter asthe diameter of the wafer 48 to be handled.

To assure that the flat portion 56 (FIG. 2) of each wafer 48 does notinterfere with accurate handling of the wafers, the vacuum wafer carrier10 has a flat contact surface 29 on its interior back side which theflat portion 56 of each wafer 48 will rest against. Elastic elements 27(FIG. 2) on the inside surface of the door 14 pushes each wafer againstthis flat surface when the door 14 is closed, so that relative movementof the wafers and the carrier during transit is minimized, that is thewafers do not rub against the ledges 60. This also assures that, whenthe door 14 is opened, the location of the flat portion 56 on each wafer48 is accurately known. That is the wafer is in a known predeterminedalignment.

In operation, after the vacuum wafer carrier 10 is in the vacuum loadlock chamber 12 with its door 14 open, the elevator drive motor 32 isoperated to bring the transfer arm 28 to just below the height of thefirst wafer 48 which it is desired to remove, and the arm drive motor 34is then operated to extend the transfer arm 28 into the interior of thecarrier 10. This is the leftmost position of the three positions of arm28 shown in FIG. 1. By operating the elevator drive motor 32 briefly,the transfer arm 28 is raised slightly until the 3 pins 50 around itscircumference 49 lift the desired wafer off of the ledges 60 (FIG. 2) onwhich it has been resting inside the vacuum wafer carrier 10.

Note that the ledges 60, as shown in FIG. 2, are tapered surfaces ratherthan flat surfaces, so that contact between the ledges 60 and the wafer48 resting on them is a line contact rather than an area contact, and islimited to the edge of the wafer. This prevents contact between carrierand wafer over a substantial area, possibly of many square millimeters,but the "line contact" used is over a much smaller area, typically of afew square millimeters or less. An alternative definition of the "linecontact" used in this embodiment is that the wafer support contacts thesurface of the wafer only at points which are less than one millimeterfrom its edge. Thus, by raising the transfer arm 28, a wafer 48 will bepicked up, and will be resting on the small cones or small shoulders1900 of the 3 pins 50 on the transfer arm 28.

The ledges 60 can have a center-to-center spacing of 0.187 inches insidethe vacuum wafer carrier 10. This center-to-center spacing, less thethickness of the wafers 48, must allow clearance enough for the heightof the transfer arm 28 plus the 3 pins 50, but need not be much more.For example, the transfer arm is about 0.080 inch thick, including theheight of the small cones 52 on the 3 pins 50. The wafer 48 can be, forexample, about 0.021 inch thick so that about 0.085 inch clearance isavailable. The thickness and diameters of the wafers can vary widely.Generally, larger diameter wafers will have greater thicknesses, butvacuum wafer carrier 10 of this kind is suited to use with such largerdiameter wafers, since the size of the vacuum wafer carrier 10 and thecenter spacing of the ledges 60 inside the vacuum wafer carrier 10 cansimply be adjusted appropriately. The carrier 10 can also be adapted tocarry thinner wafers, for example, GaAs as desired.

After the transfer arm 28 has picked up the wafer 48, the arm drivemotor 34 is operated to bring the transfer arm 28 to the home position(which is the middle position as shown in FIG. 1). This is the middleposition of arm 28 as shown in FIG. 1. The elevator drive motor 32 isthen operated to bring the transfer arm 28 to a height where it canreach through the inter-chamber transfer port 30 (FIG. 3).

The inter-chamber transfer port 30 is covered by an isolation gate 31.Although the gate 31 as shown in FIG. 3 seals the inter-chamber transferport 30 by making sliding contact. When shaft 580 is rotated (as shownin FIG. 3), the linkage provided drives gate 31 upward (as shown in FIG.3) and covers the port 30. To open the port 30 the shaft 580 is rotatedin the opposite direction. If desired the sealing can be performed by arotated movement. (Again, the absence of sliding contact may beadvantageous to reduce internally generated particulates.) The isolationgate 31 over the inter-chamber transfer port 30 can operated by anair-cylinder, but a stepper motor could be used in the alternative.Thus, a total of four motors can be used: two which use vacuumfeedthroughs, and two which are contained inside the exhaust manifold36. The arm drive motor is now operated again, to extend the transferarm 28 through inter-chamber transfer port 30 into the adjacentprocessing chamber. This is the rightmost position of arm 28 as shown inFIG. 1. The adjacent processing chamber may be any one of many differentkinds of process modules, for example, any processing module disclosedherein such as an implanter, a plasma etch, and a deposition module orany other type of process module.

The transfer arm reaching through the inter-chamber transfer port 30will place the wafer 48 on wafer support pins 53 as shown in FIG. 3,like those used in the transfer arm 28 itself. (Note that theinter-chamber transfer port 30 should have enough vertical height topermit some vertical travel while the transfer arm 28 is extendedthrough inter-chamber transfer port 30, so that transfer arm 28 can movevertically to lift a wafer from or deposit a wafer onto the wafersupport, for example, wafer support pins 53 inside the processingchamber.) The wafer 28 is deposited by arm 28 on the tops of pins 53.

Alternatively, the processing chamber may include a fixture havingspaced sloped ledges like the ledges 60 inside the transfer box, or mayhave other mechanical arrangements to receive the wafer. The arrangementused to receive the transferred wafer 48 must, however, have clearanceon the underside of the wafer (at least at the time of transfer), sothat the transfer arm 28 can reach in on the underside of the wafer toemplace or remove it. If the wafer support pins 53 are used to receivethe transferred wafer, it may be desirable to provide a bellows motionor a vacuum feedthrough in order to provide vertical motion of the wafersupport pins 53 inside the processing chamber. Thus, for example, wherethe processing chamber is a plasma etch or RIE (reactive ion etch)module, a bellows may be provided to move the wafer 48 vertically, forexample, onto a susceptor after the transfer arm 28 has been withdrawnout of the way of the wafer 48.

Of course, the processing chamber may be an engineering inspectionmodule or deposition module, for example. A vacuum-isolated microscopeobjective lens will permit inspection of wafers in vacuum and (using anappropriately folded optical path) in a face-down position. This meansthat heavy use of engineer inspection can be made where appropriate,without the loss of engineer time and clean-room quality which can becaused by heavy traffic through a clean-room. The inspection modulecould be combined with other modules if desired.

In any case, the transfer arm 28 is withdrawn, and the gate 31 is movedto the closed position to close port 30, if desired, The process ofwafer 48 then proceeds. After processing is finished, the isolation gateover the inter-chamber transfer port 30 is opened again, the transferarm 28 is extended again, the elevator drive motor 32 is operatedbriefly so that the transfer arm 28 picks up the wafer 48, and the armdrive motor 34 is again operated to bring the transfer arm 28 back intothe home position. The elevator drive motor 32 is then operated to bringthe transfer arm 28 to the correct height to align the wafer 48 with thedesired slot inside the vacuum wafer carrier. The arm drive motor 34 isthen operated to extend the transfer arm 28 into the vacuum wafercarrier 10, so that the wafer 48 which has just been processed issitting above its pair of ledges 60. The elevator drive motor 32 is thenbriefly operated to lower the transfer arm 28, so that the wafer isresting on its own ledges 60, and the arm drive motor 34 is thenoperated to retract the transfer arm 28 to home position. The sequenceof steps described above is then repeated, and the transfer arm 28selects another wafer for processing.

Note that, with the mechanical linkage of the transfer arm 28 androtatable transfer arm support 44 described above, the wafers beingtransferred will move in exactly a straight line if the center to centerlengths of transfer arm 28 and transfer arm support 44 are equal. Thisis advantageous because it means that the side of the wafer beingtransferred will not bump or scrape against the sides of the vacuumwafer carrier 10 when the wafer is being pulled out of or pushed intothe box. That is, the clearances of the vacuum wafer carrier 10 can berelatively small (which helps to reduce particulate generation byrattling of the wafers during transport in the carrier) without riskingparticulate generation due to abrasion of the wafers against the metalbox sides.

Processing continues in this fashion, wafer by wafer, until all thewafers inside the vacuum wafer carrier 10 (or at least as many of themas desired) have been processed. At that point the transfer arm 28 isreturned empty to its home position and lowered below the lower edge ofthe door 14, and the isolation gate 31 over inter-chamber transfer port30 is closed. Shaft 24 is rotated to close door 14 and provide initialcontact for the vacuum seals between door 14 and the flat front surfaceof vacuum wafer carrier 10, so that the vacuum wafer carrier 10 is readyto be sealed (by pressure differential) as the pressure inside the loadlock is increased. The vacuum load lock chamber 12 can now bepressurized again. When the differential sensor of the vacuum gauges 62determines that the pressure has come up to atmospheric, the load locklid 20 can be opened and the vacuum wafer carrier 10 (which is nowsealed by differential pressure) can be manually removed. A foldinghandle 11 is usefully provided on the top side of the carrier, to assistin this manual removal without substantially increasing the volumerequired for the vacuum wafer carrier 10 inside the load lock.

After the vacuum wafer carrier 10 has been removed, it can be carriedaround or stored as desired. The vacuum seal 13 will maintain a highvacuum in the vacuum wafer carrier 10 so that particulate transport tothe wafer surfaces (and also adsorption of vapor-phase contaminants) isminimized. The surface of wafers within the carrier 10 have the surfacewhich is being processed to construct devices are facing downward toprevent particulates from settling on that surface.

Note that the vacuum wafer carrier 10 also includes elastic elements 27mounted in its door. These elastic elements 27 exert light pressureagainst the wafers 48 when the door 14 is closed, and thus restrain themfrom rattling around and generating particulates. The elastic elements27 are configured as a set of springs in the embodiment shown, but othermechanical structures (e.g. a protruding bead of an elastic polymer)could alternatively be used to configure this. Where the wafers usedhave flats, a flat contact surface 29 is provided on the inner backsurface of the vacuum wafer carrier 10 for the wafer flats to be pressedagainst.

Note also that the ledges 60 on the sidewalls of the vacuum wafercarrier 10 are tapered. This helps to assure that contact with thesupported surface of the wafer is made over a line only, rather thanover any substantial area. This reduces wafer damage and particulategeneration during transport. This also assists in damping out theaccumulation of positioning errors, as discussed. The load lock lid 20can have a window (not shown), to permit inspection of any possiblemechanical jams.

An advantage of such embodiments is that, in the case of many possiblemechanical malfunctions, the door of the vacuum wafer carrier 10 can beclosed before attempts are made to correct the problem. For example, ifsomehow the transfer arm 28 picks up a wafer so that the wafer is notsitting properly on all three of the 3 pins 50, the door drive motor 26can be operated to close the door 14 before any attempts are made tocorrect the problem. Similarly, the inter-chamber transfer port 30 canbe closed if the transfer arm 28 can be retracted into home position. Itmay be possible to correct some such mechanical misalignment problemssimply by deviating from the normal control sequence. For example, theposition of a wafer 48 on the transfer arm 28 may in some cases beadjusted by partially extending the transfer arm 28, so that the edge ofthe wafer 48 just touches the outside of the door 14, or of theisolation gate over the inter-chamber transfer port 30. If this does notwork, the vacuum load lock chamber 12 can be brought back up toatmospheric pressure (with the door 14 of vacuum wafer carrier 10closed) and the load lock lid 20 opened so that the problem can bemanually corrected.

FIG. 4 shows a single wafer reactor which can be used for that can beused for remote plasma enhanced chemical vapor deposition as well asother functions. As discussed above, the transfer arm 28 places a waferonto the wafer support pins 53 (FIG. 3) and then retracts. At this pointthe whole lower assembly, including the process gas distributor 218,feed 250, ring 576 and ultraviolet plasma space 220 are moved upward,using, e.g., an air cylinder of a vacuum feed through (not shown). Abellows 124 permits this vertical motion to occur while maintaining avacuum-tight interface to the interior of the module 570. This verticalmotion causes the backside of the wafer resting on the wafer supportpins 53 to make contact with the the transparent vacuum wall 238. Atthis point, the sliding pin supports 130 which are attached to theunderside of the wafer support pins 53 retract slightly against a leafspring 132. (Other elastic elements could be used in place of leafspring 132, to assure a small amount of give in the sliding pin supports130, so that the wafer is not pressed against the transparent vacuumwall 238 with too much force.)

The last portion of the upward travel of this assembly causes the seal135 (FIG. 3) to make closure between the process chamber and thetransparent vacuum window 238. Thus, when the seal is made, the interiorof this process chamber is vacuum-sealed from the remainder of theinterior of process module 570.

At the same time, desired process gases can be provided through aprocess gas distributor 218. The process gas distributor 218 is made ofquartz, so that it does not pick up eddy currents from the RF powerpresent. Moreover, since the surface of the quartz is highly insulating,the plasma boundary near the quartz will not have as much voltage nor asmuch current across it as the plasma boundary near a grounded conductiveelement would. This means that plasma-assisted reactions near the quartzwill not occur at as high a rate as they would near a groundedconductive element, so that deposition is reduced. It should also benoted that quartz is a fairly good thermal insulator, and thetemperature of the susceptor may therefore be raised (by radiation fromthe plasma) to 100 or 200 degrees C. This is advantageous for someprocesses, since raising the temperature of the distributor will furtherreduce deposition on it. The process gas distributor 218 is a ring, ofperhaps one-half the diameter of the wafer being processed, with hollowsupports which lead down to gas connections 140. A quick-connectmounting is provided for the quartz process gas distributor 218, so itcan rapidly and easily be changed out as desired.

The process gas distributor 218 is usefully spaced away from the surfaceof the wafer by only four centimeters, for example. This spacing, andthe exact shape of the process gas distributor 218, and the feed 250 arenot critical. These parameters can be changed if desired, but, ifmodified, they should be selected so that diffusion of process gases andprocess gas products from the feed 250 in the process gas distributor218 provides: (1) diffusion-dominated transport of the process gases andprocess gas products to the plasma boundary at the face of the wafer 48;and (2) a fairly uniform concentration of process gases and process gasproducts at the plasma boundary next to the face of wafer 48. Forexample, the spacing of the process gas distributor 218 away from thewafer face could be anywhere in the range from one to fifteencentimeters.

After the desired operation is finished, the gas supplied throughprocess gas distributor 218 is cut off, and the process module 570 ispumped down to the same pressure as the rest of the process module (10to the -3 Torr or less). A holding time may then be interposed, forthermal stabilization of the process module or for release of possiblesuspended particulates, and then the process module 570 is opened andarm 28 operates as described above to remove the wafer from chamber 12.The position of the arm 28 with the chamber 12 would be the rightmostposition of arm 28 shown in FIG. 1.

Note that all of the operations described above can be very easilycontrolled. No servos or complex negative feedback mechanisms areneeded. All the motors described are simple stepper motors, so thatmultiple modules of this type can be controlled by a single computercontrol system 206 (FIG. 5). The mechanical stability of the system as awhole --i.e. the inherent correction of minor positioning errorsprovided by the tapering of the wafer support pins 53, by the slope ofthe ledges 60 in the wafer carrier, and by the flat contact surface 29on the backwall of the vacuum wafer carrier 10--helps to preventaccumulation of minor errors, and facilitates easy control.

This advantage of simple control is achieved in part because goodcontrol of mechanical registration is achieved. As noted, the docking ofthe vacuum wafer carrier 10 with position registration platform 18provides one element of mechanical registration, since the location ofthe position registration platform 18 with respect to the transfer arm28 can be accurately and permanently calibrated. Similarly, the vacuumwafer carriers 10 do not need to be controlled on each dimension, butmerely need to be controlled so that the location and orientation of theledges 60 are accurately known with respect to the bottom (or otherportion) of the vacuum wafer carrier 10 which mates with positionregistration platform 18. As described above, this is accomplished byhaving channels which the vacuum wafer carrier 10 slides into until itrests on the position registration platform 18, but many othermechanical arrangements could be used instead. Various types ofelectronic mechanical sensors could provide information about theposition and operation of the system for further control and correctiveaction by the computer control system 206.

Similarly, mechanical registration must be achieved between the homeposition of the transfer arm 28 and the 3 pins 50 (or other supportconfiguration) which the wafer will be docked to inside the processingchamber. However, this mechanical registration should be a simpleone-time setup calibration. Note that angular positioning will bepreserved by the vacuum wafer carrier itself, as was noted, whenever thedoor 14 is closed, spring elements inside it will press each wafer 48against the flat contact surface 29 of the vacuum wafer carrier 10.Optionally, the vacuum wafer carrier 10 could be provided with aquick-connect vacuum fitting, to permit separate pumpdown on the vacuumwafer carrier 10.

It should be noted that the load lock mechanism described need not beused solely with vacuum wafer carriers 10, although that has been couldto be useful. This load lock can also be used with wafer carriers whichcarry atmospheric pressure inside. Although this is an alternativeembodiment, it still carries substantial advantages, as is discussedabove, over prior art load lock operations such as that shown in U.S.Pat. No. 4,609,103, by Bimer et al, issued on Aug. 27, 1984, which isincorporated by reference hereinto.

It should be noted that a vacuum wafer carrier 10 as described can bemade in different sizes, to carry any desired number of wafers.Moreover, a vacuum wafer carrier 10 of this kind can be used to carry orstore any desired number of wafers, up to its maximum. This providesadditional flexibility in scheduling and process equipment logistics. Aclosed loop particle control system is usefully provided to control theoperation of the load lock and the process chamber before and afterprocessing operations.

Module 570 shown in FIG. 4, includes the capability for processenhancement by ultraviolet light generated in situ and the capability isalso provided for providing activated species, generated by gas flowsthrough an additional plasma discharge which is remote from the waferface to the wafer face. The module is shown in a process station 570which includes only one module and one vacuum load lock, but can also beused in embodiments where a central handling chamber is combined withplural process modules 570 and one or more vacuum load lock chambers 12.

Note that a particulate sensor 202 (FIG. 4) is explicitly shownconnected to the interior of the vacuum load lock chamber 12. Thisparticulate sensor 202 need not be physically located very close to thedocking position of vacuum wafer carrier 10, as long as the signal fromparticulate sensor 202 does provide an indication of the level ofparticulates present in the interior of the vacuum load lock chamber 12.The particulate sensor 202 is usefully located downstream from thevacuum load lock 12, in the pump out path (not shown). The particlesensor is a commercially available laser particle counter (which detectsindividual particles) combined with a counter which provides an outputsignal showing the number of particles counted over a certain timeduration. The ultraviolet plasma space 220 is supplied with a gas usefulfor the production of ultraviolet light, for example, H₂, Ar, or Hethrough ring 576. The frequency of the power utilized to generate theultraviolet light can be, for example, 100 KHz or 13.56 MHz. The module570 has a process chamber 218 which can have gas introduced througheither a distributor 212 or feed 250. Ozone, for example, could be feedthrough distributor 212. A transparent vacuum wall 238 allow the radiantheat from a heating module 572 to pass through to wafer 48 below.

The following processes can also be used with FIG. 4 and the otherprocess modules which have ultraviolet light and remote plasmacapability.

Module 570, shown in FIG. 4, can perform the deposition of polysiliconutilizing a silicon containing gas (for example, silane or disilane) andeither or both an additional ultraviolet generated inside module 570(which is directly optically coupled into the process chamber 218) and aremotely generated plasma from remote plasma chamber 254.

For example, a silane gas is introduced into the process chamber. If theremote plasma is not used then the silane gas can also be introducedinto chamber 218 through distributor 212. The chamber should bemaintained at deposition temperature. After the wafer is disposed withchamber 218, a purge can be performed if desired by utilizing anappropriate gas which is non-reactive with the wafer and the exposedlayers thereon, for example, N₂. An example of this process follows: Thewafer is placed in the chamber. The chamber is evacuated and purged withN₂ (in general the pressures usable within the chamber are between 0.1to 750 Torr). A remote plasma is generated within chamber 254 fromsilane gas. The remote plasma is introduced into the chamber 218 and tothe downward facing face 54 of wafer 48. The chamber is heated to thedeposition temperature of, for example, 550 to 700 degrees C. Additionalultraviolet energy is coupled into chamber 218 from space 220 byexciting the gas therein, for example, H₂, Ar, or He introduced throughring 576 using a power of 300 watts at a frequency of 100 KHz. Thereaction is as follows:

    SiH.sub.4 >SiH.sub.2 +Si.sub.2 H.sub.6 >Polysilicon+H.sub.2

where the light enhances deposition by increasing the molecularexcitation level. The gases and heat is turned off and the chamber isagain purged, with an appropriate gas, if desired. The wafer is thenremoved. A cleaning step can then be performed as desired utilizing aremote plasma formed from a mixture of HCl and HBr.

Module 570 can also perform the deposition of polysilicon utilizingeither or both ultraviolet energy generated inside module 570 and aremotely generated plasma from remote plasma chamber 254 and in which adisilane gas is introduced into the process chamber. If the remoteplasma is not used then the disilane gas can also be introduced intochamber 218 through distributor 212. The chamber should be maintained atdeposition temperature. After the wafer is disposed with chamber 218, apurge can be performed if desired by utilizing an appropriate gas whichis non-reactive with the wafer and the exposed layers thereon, forexample, N₂. An example of this process follows: The wafer is placed inthe chamber. The chamber is evacuated and purged with N₂ (in general thepressures usable within the chamber are between 0.1 to 750 Torr). Aremote plasma is generated within chamber 254 from disilane gas. Theremote plasma is introduced into the chamber 218 and to the downwardfacing face 54 of wafer 48. The chamber is heated to the depositiontemperature of, for example, 550 to 700 degrees C. Additionalultraviolet energy is coupled into chamber 218 from space 220 byexciting the gas therein, for example, H₂, Ar, or He introduced throughring 576 using a power of 300 watts at a frequency of 100 KHz. Thereaction is as follows:

    Si.sub.2 H.sub.6 +Hν>nSi-Si.sub.g *+nH.sub.2 +heat>xSi.sub.solid

where the light enhances deposition by increasing the molecularexcitation level. The gases and heat are turned off and the chamber isagain purged, with an appropriate gas, if desired. The wafer is thenremoved. A cleaning step can then be performed as desired utilizing aremote plasma formed from a mixture of HCl and HBr.

In addition, either of the processes described above can be used todeposit a doped polysilicon. The particular dopant (for example,diborane, boron trichloride, phosphine, phosphorous trichloride, ortertiary butyl phosphine) is added to the silane or disilane, inappropriate amounts, prior to the silane or disilane mixture beingintroduced to the remote plasma chamber 254. If remote plasma is notused, the dopant and silane or disilane mixture can also be introducedinto chamber 218 through distributor 212. The balance of the processremains the same.

The culmination of the processing of wafer 48 can be electronic devicesfor example, integrated circuits or discrete semiconductor devices. Oncethe processing is completed the wafers are divided into devices. Thecircuits and devices are enclosed into packages, for example, as shownin U.S. Pat. Nos. 4,465,898 issued to Orcutt et al on Aug. 14, 1984 and3,439,238 issued to Birchler et al on Apr. 15, 1969, which areincorporated hereinto by reference. These packages are then utilized inthe construction of printed circuit boards. The printer circuits boards,which cannot operate without the packaged integrated circuits anddevices to perform their intended functions, are the required electricalcomponents within computers, photocopiers, printers, telecommunicationequipment, calculators, and all of the other electronic equipment whichare an essential ingredients of the electronic and information age. Thuselectronic equipment cannot function with the circuits and devices.

The present application describes a number of processing methods, whichrespectively contain numerous additional features which serve to providefurther advantages.

The present invention advantageously allows variable polysilicondeposition rates.

It is another advantage of the present invention that appropriatelydoped polysilicon can be deposited.

It is yet another advantage of the present invention that a remotelygenerated microwave plasma can be used to clean the chamber each time itis used, making the deposition chamber clean for the next use.

A further of the present invention is it advantageous use of ultravioletenergy to enhance the deposition rate.

It is an advantage of the present invention to provide a process for thedeposition of polysilicon which allows for the selective utilization ofeither or both of addition Ultraviolet light and remote plasma asdesired.

It is an advantage of the present invention to provide an apparatus andmethod of deposition of polysilicon which allows improved controlthereof by providing a wider range of available gas flows, temperaturesand pressures.

Having described the invention in connection with certain specificembodiments thereof, it is to be understood that further modificationsmay now suggest themselves to those skilled in the art, it is intendedto cover all such modifications as fall within the scope of the appendedclaims.

What is claimed is:
 1. A method for depositing polysilicon on a wafer comprising;(a) disposing a wafer into a process chamber of a process module; (b) purging the process vacuum process chamber with an appropriate gas; (c) applying a pressure to said chamber less than ambient to maintain said chamber at less than ambient; (d) heating the chamber; (e) generating a remote plasma from a silicon containing and a dopant gas; (f) presenting said remote plasma to a face of said wafer in said chamber; (g) providing a separate flow, within said chamber, of a gas suitable for the production of ultraviolet light; (h) generating an RF power discharge within said separate flow to release ultraviolet energy; and (i) illuminating said face of said wafer with said ultraviolet energy generated inside said module.
 2. The process as set forth in claim 1 wherein the dopant gas is a phosphorous containing gas taken from the group containing; phosphine, phosphorous trichloride, or tertiary butyl phosphine.
 3. The process as set forth in claim 1 wherein the dopant gas is a boron containing gas taken from the group containing; diborane or boron trichloride
 4. The process as set forth in claim 1 wherein the dopant gas is a phosphorous containing gas.
 5. The process as set forth in claim 1 wherein the dopant gas is a boron containing gas.
 6. The process as set forth in claim 1 wherein the silicon containing gas is disilane.
 7. The process as set forth in claim 1 wherein the silicon containing gas is silane.
 8. A method for depositing polysilicon on a wafer, comprising the steps of:(a) generating free radicals from a silicon containing gas and a dopant gas in a plasma generating chamber remote from the process chamber; (b) introducing the free radicals to a face of the wafer in the process chamber; (c) providing a separate flow, within said process chamber, of a gas suitable for the production of ultraviolet light; (d) generating an RF power discharge within said separate flow to release ultraviolet energy; and (e) illuminating the face of the wafer with ultraviolet energy which is generated inside the module.
 9. The process as set forth in claim 8 wherein the dopant gas is a phosphorous containing gas taken from the group containing phosphine, phosphorous trichloride, or tertiary butyl phosphine.
 10. The process as set forth in claim 8 wherein the dopant gas is a boron containing gas taken from the group containing diborane or boron trichloride.
 11. The process as set forth in claim 8 wherein the dopant gas is a phosphorous containing gas.
 12. The process as set forth in claim 8 wherein the dopant gas is a boron containing gas.
 13. The process as set forth in claim 8 wherein the silicon containing gas is disilane.
 14. The process as set forth in claim 8 wherein the silicon containing gas is silane. 